This project is investigating the mechanisms governing the synthesis and secretion of pituitary hormones by the pituitary gland. Of particular interest is the mechanism whereby hypothalamic dopamine and serotonin function. The biochemical and pharmacological constraints on the binding of H3-dopamine to bovine pituitary membranes are being studied by in vitro techniques. A new pituitary gland cell dispersion technique is being developed which will allow the entire population of pituitary cells or a selected population of cells to be superfused by tissue culture media and the amounts of PRL, GH and ACTH measured in the effluent. Animals will be injected with agents known to alter the catecholamine and indolamine content and turnover and hypothalamic extracts prepared. The dispersed cells will then be superfused with these extracts.